Estimating extractable soil moisture content for Australian soils from field measurements

Soil Research ◽  
2006 ◽  
Vol 44 (5) ◽  
pp. 531 ◽  
Author(s):  
A. R. Ladson ◽  
J. R. Lander ◽  
A. W. Western ◽  
R. B. Grayson ◽  
Lu Zhang
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Transfer Functions ◽  
Vegetation Type ◽  
Field Measurements ◽  
Pasture Production ◽  
Soil Moisture Storage ◽  
Moisture Storage ◽  
Extractable Soil

The amount of water that can be stored in soil and evaporated or actively used by plants is a key parameter in hydrologic models and is important for crop and pasture production. Often, the active soil moisture store is estimated from laboratory measurements of soil properties. An alternative approach, described in this paper, is to estimate the extractable soil moisture capacity from direct measurements of soil moisture content in the field. A time series of soil moisture values, over the depth of the soil, shows the actual changes in water content. The difference between the wettest and driest profiles is an estimate of the extractable soil moisture storage. We have gathered data on extractable soil water capacity for 180 locations over Australia and have compared our values with published results from the Atlas of Australian Soils (AAS), derived from profile descriptions and pedo-transfer functions. Our results show that data from the AAS provide a useful lower bound for measured extractable soil moisture storage, but of the sites examined, 42% had values >2 times those in the AAS. In part, this was because total soil depths were underestimated in the AAS results compared with the active depths from the measured data. Active depths are strongly related to vegetation type.

Thermal properties of Antarctic soils: wetting controls subsurface thermal state

2016 ◽  
Vol 28 (5) ◽  
pp. 361-370 ◽  
Author(s):  
Joseph S. Levy ◽  
Logan M. Schmidt
Keyword(s):  
Soil Moisture ◽  
Thermal Diffusivity ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Thermal State ◽  
Thermal Characteristics ◽  
Field Measurements ◽  
Dry Valleys ◽  
Ground Ice ◽  
Mineral Soils

AbstractMineral soils in the McMurdo Dry Valleys (MDV), Antarctica, are commonly considered to be dry, and therefore to be good insulators with low thermal diffusivity values (~0.2 mm2s-1). However, field measurements of soil moisture profiles with depth, coupled with observations of rapid ground ice melt, suggest that the thermal characteristics of MDV soils, and thus their resistance to thaw, may be spatially variable and strongly controlled by soil moisture content. The thermal conductivity, heat capacity and thermal diffusivity of 17 MDV soils were measured over a range of soil moisture conditions from dry to saturated. We found that thermal diffusivity varied by a factor of eight for these soils, despite the fact that they consist of members of only two soil groups. The thermal diffusivity of the soils increased in all cases with increasing soil moisture content, suggesting that permafrost and ground ice thaw in mineral soils may generate a positive thawing feedback in which wet soils conduct additional heat to depth, enhancing rates of permafrost thaw and thermokarst formation.

scholarly journals Effect of Vegetation Restoration on Soil Hydrology in Karst Area of Southwest China: Inspiration from Barrel Planting Experiments

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1719
Author(s):  
Ziqi Liu ◽  
Rong She ◽  
Kangning Xiong ◽  
Yuan Li ◽  
Lulu Cai
Keyword(s):  
Soil Moisture ◽  
Vegetation Type ◽  
Water Shortage ◽  
Vegetation Restoration ◽  
Karst Area ◽  
Stable Range ◽  
Soil Hydrology ◽  
Soil Moisture Storage ◽  
Moisture Storage ◽  
Zanthoxylum Bungeanum

The purpose of this study was to explore the effects of different vegetation restoration types on soil hydrology characteristics in the Karst Plateau Gorge and to clarify the soil moisture (θ) use characteristics. A barrel experiment was conducted to monitor θ and the water potential (Ψ) of three vegetation types (Zanthoxylum bungeanum (ZB), Zea mays L. (ZM), and Sophora tonkinensis (ST), Abandoned land (AL)) was used as a control to explore θ use conditions of each vegetation type. A larger surface permeability led to lower moisture storage. The soil moisture storage showed the law of ZM > ST > AL > ZB. The soil moisture storage also had obvious characteristics in dry-wet seasons. As a typical drought-tolerant crop, ZB responded more obviously to rainfall and had the highest effective replenishment amount and efficiency. Two processes were clearly involved in decreasing soil moisture, which could be divided into three stages of changes: a consumption period (CP), a moisture supplying period (SP), and a relatively stable period (RSP). CP occurred primarily in November to April, when θ was prone to water stress and required proper artificial replenishment. SP was characterized by limited rainfall replenishment in January and May, which significantly increased θ. During the rainy season, corresponding with RSP, θ fluctuated within a relatively stable range. At the end of the CP, the water shortage was more severe. In actual agricultural production, attention should be given to reasonable artificial recharge. This research aims to provide a theoretical basis for karst θ management.

scholarly journals SHORT TDR PROBES TO MEASURE WATER AND FERTILIZER ION GRADIENTS IN CONTAINER MEDIA

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 742c-742
Author(s):  
Shaun F. Kelly ◽  
J.L Green ◽  
John S. Selker
Keyword(s):  
Porous Media ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Steel Wire ◽  
Field Measurements ◽  
Time Domain Reflectometry ◽  
Ion Concentrations ◽  
High Bandwidth ◽  
High Concentrations

Time Domain Reflectometry (TDR) is used to measure in situ soil moisture content and salinity of porous media. Commercially available TDR systems used for field measurements have limited use in laboratory scale experiments where short high resolution probes are needed. A short TDR probe was designed for use with high bandwidth TDR instruments currently available. The probes are designed from SMA bulkhead connectors using gold-plated stainless steel wire 0.035 inches in diameter. A 20.GHz digital sampling oscilloscope (11801; Tektronix, Beaverton, Ore.) with an SD-24 TDR sampling head is used with the probes to determine water content and ion concentrations in porous media. The 7.5- and 3.0-cm-long probes were used to measure soil moisture content and ion concentrations in laboratory columns. Fertilizer and water gradients were observed by using bromide salts brought into contact with the top of laboratory columns, 7.6 cm in diameter and 18 cm long, packed with container media [1 peat: 1 vermiculite v/v)]. Soil moisture measurements in the presence of high concentrations of salts were made by insulating the probes with Teflon heat-shrinkable tubing to minimize conductivity losses.

Numerical Simulation of Terrestrial Radiation over a Snow Cover

2015 ◽  
Vol 32 (8) ◽  
pp. 1478-1485 ◽  
Author(s):  
P. Ducharme ◽  
A. Houdayer ◽  
Y. Choquette ◽  
B. Kapfer ◽  
J. P. Martin
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Snow Water Equivalent ◽  
Field Measurements ◽  
Radioactive Material ◽  
Gamma Detector ◽  
Content Type ◽  
Basic Assumptions ◽  
Snow Water

AbstractThe intensity of terrestrial gamma radiation is a function of a number of parameters: emissivity and spatial distribution of the radioactive material in the soil, snow/water cover above ground, soil moisture content, type, and height above ground of the detector. Thus, the conversion of gamma measurements into reliable information must be based on a solid knowledge of the behavior of the gamma detector under different conditions. Such a detector, using a cylindrical NaI(Tl) crystal, was developed to remotely and automatically provide information on snow water equivalent (SWE) and soil moisture content (M). It became rapidly obvious that the behavior of the detector [gamma monitor (GMON)] over an infinite source could not be exactly reproduced in a laboratory. Therefore, a relatively simple model to simulate the behavior of GMON and to establish the relevant data analysis algorithms was conceived. This paper presents the basic assumptions for developing the model, the resulting algorithms, a comparison with field measurements, and some useful information on how GMON reacts to various field conditions.

scholarly journals SOIL MOISTURE AVAILABILITY IN AN ORCHARD AND THE NEED FOR ITSREGULATION

2021 ◽  
pp. 37-43
Author(s):  
S.V. Makarychev ◽  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Steppe Zone ◽  
Apple Orchard ◽  
Limiting Factor ◽  
Forest Steppe ◽  
Apple Trees ◽  
Soil Moisture Storage ◽  
Available Soil Moisture ◽  
Moisture Storage

The growth and fruiting of fruit crops is interconnected with the biotic and abiotic conditions of the natural envi-ronment as water, heat and nutritional regimes in the soil which continuously change in space and time. The main limiting factor in the forest-steppe zone of the Altai Region is the moisture content in the soil profile since plants often suffer from moisture deficit. The available soil moisture (ASM) storage in the apple orchard in April 2012 was satis-factory. In Mayand in the summer, they dropped to zero, so the plants suffered from water hunger during the grow-ing season. Under pears, at the beginning of the growing season, the ASM turned out to be higher than under the apple trees, but from June to August they alsodecreased. As a result, the irrigation rates were the same as for the apple trees. The summer of 2013 was rainy and that af-fected the water resources in the chernozem layer. At the same time, the ASM deficit did not exceed 85 mm in June and July, and in the remaining periods did not rise above 50 mm. In the pear orchard, the moisture storage did not fall below 30 mm. In one-meter chernozem layer in April 2012, the available soil moisture storage under the apple trees corresponded to a very good level. In June and July, the moisture content dropped below the wilting moisture. In spring, the ASM under the pear plantations were consid-ered satisfactory. On the following months, a severe mois-ture deficit arose until autumn. In 2013, the ASM in the apple orchard did not exceed 50 mm in summer. Under the pears, in May they even reached 118 mm, but then dropped to 30 mm and that also required irrigation. Since the season of 2014 was an arid one, the water situation in one-meter layer of chernozem turned out to be disastrous.

Effect of different types of soil tillage for sunflower on some soil physical characteristics. Part I: soil moisture

Helia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Peter Yankov ◽  
Miglena Drumeva
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Layer ◽  
Soil Tillage ◽  
No Tillage ◽  
Plant Available Water ◽  
Moisture Storage ◽  
Direct Sowing ◽  
Wilting Point

Abstract The investigation was carried out during 2014–2016 in the land of General Toshevo town in the South Dobrudzha region on slightly leached chernozem soil type. The effect of the types of soil tillage for sunflower given bellow was followed: ploughing at 24–26 cm, chisel-plough at 24–26 cm, disking with disk harrow at 10–12 cm and direct sowing (no-tillage) on the soil moisture content. Based on bulk density, wilting point and the determined soil moisture content the plant-available water was calculated. The additional soil tilths of the areas subjected to ploughing, chisel-ploughing and disking with disc harrow included double spring pre-sowing cultivation with harrowing. To destroy the emerging weeds in the variant with direct sowing, a total herbicide was applied. The soil moisture content was evaluated during three main stages of sunflower development: emergence, flowering and technical maturity. The investigated parameter was determined for each of the studied layers – 0–10, 10–20, 20–30, 30–40 and 40–60 cm. In years with normal amounts of rainfalls, no significant differences in the soil moisture under the different ways of soil tillage were observed. Conventional ploughing and tillage without turning of the soil layer contributed to accumulation of more moisture and to higher moisture storage down the soil profile under heavy and intensive rainfalls. Tillage without turning of the soil layer, minimal and no tillage maintained more and better soil moisture in years with limited precipitation and in periods of drought.

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River

Distribution of soil moisture content and its effect on the potential growth of the over-story species in North-East Chalkidiki

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Depth ◽  
Moisture Distribution ◽  
Taxus Baccata ◽  
Mixed Stands ◽  
Potential Growth ◽  
North East ◽  
Soil Moisture Distribution

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.

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